[lammps-users] Group force

Dear all,

I want to do a indent simulation with the aid of LAMMPS, there are a specimen and a indenter in the simulation. And I want to obtain the indenter’s y-direction force, as normal force. The command “compute 1 indenter reduced fy” is adopted to obtain the normal force. However, the force-displacement curve obtained is not agree with my expection, which is shown is attached Figure 1. From some papers published about the indentation process, the force-displacement curve should has the similar trend of the attached Figure 2. So I really don’t know what’s wrong with the force date obtained. Will anybody give me some advice?

Best ragards
Damien

2008-03-29

Figure 2.jpg

Figure 1.jpg

How are you doing the indentation? Is there something forcing
the indenter into the surface? Are you subtracting out that force?

Steve